1. Field
The disclosed subject matter relates generally to wireless communication. In particular, the disclosed subject matter relates to power control of signals transmitted in wireless communication systems.
2. Description of the Related Art
Communication over a wireless channel can be accomplished using a variety of techniques which facilitate a large number of users in a limited frequency spectrum. These techniques, commonly referred to as multiple access techniques, include time division multiple access (TDMA), frequency division multiple access (FDMA), and code division multiple access (CDMA).
CDMA offers many advantages over other modulation techniques used in wireless communication systems such as TDMA and FDMA. For example, CDMA permits the frequency spectrum to be reused multiple times, thereby permitting an increase in system user capacity. Additionally, use of CDMA techniques permits the special problems of the terrestrial channel to be overcome by mitigation of the adverse effects of multipath, e.g. fading, while also exploiting the advantages thereof.
In CDMA and other wireless communication technologies, it is often desirable to increase the number of simultaneous users the communication system can accommodate. A technique that is often used to increase the number of simultaneous users is to adjust the power of the signal transmitted by a wireless communication device (WCD) so as to decrease its interference with signals transmitted by other WCDs. If the power of the signal transmitted by a WCD is adjusted so the signal-to-interference ratio is at a minimal acceptable level when the signal is received at its desire destination then the system capacity can be increased. Because signals transmitted by one WCD will interfere with signals transmitted by other WCDs, decreasing the power of signals transmitted by a WCD will decrease the overall interference in the system and thus the system capacity can be increased. For example, if there are multiple WCDs communicating with a base station, the number of WCDs that can simultaneously communicate will be maximized if all of the WCDs decrease the power of their transmitted signals to a minimum level while still maintaining sufficient power to achieve a minimum signal-to-interference ratio at the base station receiver.
There is therefore a need in the art for techniques to provide improved power control of signals transmitted between WCDs and base stations in a wireless communication system.